running a class: lab management

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Running a class:Lab Management

Niky Riga

GENI Project Office

Sponsored by the National Science Foundation 2Train the TA – Sept 13, 2012

Timeline/Checklist

1. Notify help@geni.net

2. Determine how your students will login to GENI

3. Create a project for the class

4. Choose exercises and test them

5. Decide what machine/software the students

should use

6. Pre-work

7. bulk add attendees to the project

8. Do exercise

Sponsored by the National Science Foundation 3Train the TA – Sept 13, 2012

Timeline/Checklist

1. Notify help@geni.net

2. Determine how your students will login to GENI

3. Create a project for the class

4. Choose exercises and test them

5. Decide what machine/software the students

should use

6. Pre-work

7. bulk add attendees to the project

8. Do exercise

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Exercises – Assignments Available Exercises

Create your own

Slice setup

Notify resource providers

Student setup

Debugging

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Available Exercises

• List of sample assignments and tutorials:– Use as they are– Modify to meet your needs

• Annotated:– Type – Purpose– Resources needed– Difficulty/Duration

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Available Exercises

• Each sample exercise has:– Handouts / Instructions for students– Further information about the instructors– For solutions email help@geni.net

• Instruction format:– 3 Steps based on standard experiment

lifecycle

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Create your own

1. Figure out GENI Resources

2. Test your exercise

3. Adjust writeup

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Create your own: GENI Resources

• Compute resources:– Wired / Wireless– Are VMs ok?

• Networking requirements• Tools

– Flack, Omni, I&M

List per student/group:GENI resourcesTools

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Create your own: Test

• Run through the exercise

• Automate:– Install scripts (HowTo/WriteInstallScripts)– Custom Image

RSpec for exercise Install scriptsCustom image

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Create your own: WriteUp

• Decide what students should hand in:– Screenshots– Commands– Configuration

• Should they leave the slice up?– Login and test their environment

• Online template for instructions

Remember to include clean up!

Send us your exercise!

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Slice Setup: Student Setup Slice

Research AsstSlice Lead Post-Doc

Slice MemberProfessor

Slice Admin

Need to provide:• RSpec:

– Students might create their own (e.g. LabZero)– URL, File, Upload it in Portal

• AMs for students to use• Preferred tool

– Flack, Omni, Portal

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Slice Setup: Premade slices

Lab Exercises: Resource reservation might take time

Assignments: Resource reservation is complicated/unique or out of scope

1. Create a slice per student/group

2. Make the student(s) member of the slice• Ensure they have keys (email us if needed)

3. Reserve resources from the Portal

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Load Balance the students

• Split students/groups between equivalent resources (e.g. racks) to avoid resource contention

• If using scarce resources consider a rolling deadline

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Notify Resource GMOC

GMOC: GENI Meta-operation Center• Keeps track of outages• Notification system for resource reservation

http://groups.geni.net/geni/wiki/HowTo/PreReserveGENIResources

GMOC Google Calendar keeps track of reservations/outages

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Exercises – Assignments

Student setup Native Setup

Setup using a VM

How to chose

Debugging

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Native Setup: Student’s laptop

If students will use their personal computer, (e.g. laptop):• Make a list of all tool requirements (e.g. Flack

needs Flash installed)• Ensure that they can install/use all tools

needed for exercise (e.g. they can ssh)

Make sure they test it early in the class. LabZero is a good way to do this!

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Native Setup: Lab Computers

If students will use lab computers:

• Install and test tools in the machines– Go through the exercises in the lab

• If there are specific times the lab is open, stress-test the resources or split students

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Setup using a VM

You can create a VM:• install all tools

– Go through the exercises from the VM

• students use VirtualBox to load the VM– You can use any Virtualization solution you want– http://groups.geni.net/geni/wiki/HowTo/CreateTutorialVM

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VM or not? How to chose

Use a VM if:Want to use Omni – coming soon windowsStudents are not very familiar with computer

admin (e.g. offering a cross-discipline course)This is a one-time tutorialUniform environment

Easier to help students Easier to write instructions

Use native setup if: Students will use GENI for research Students in class are future TAs

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Exercises – Assignments

Student setup

Debugging

Slice access

Common problems

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Slice Access

Research AsstSlice Lead Post-Doc

Slice MemberProfessor

Slice Admin

Members of all slices:• Project Leads (Professor)• Project Admins (TAs, Graders) – coming soon!

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Slice Access

Being a member of a slice means you can act on a slice:– Add resources– Check status– Delete resources– Renew resources

With any tool!

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Slice Access: Logging in to resources

Slice membership does not guarantee ability to login to resources!

To ensure access in student’s resources:Option 1: Make resource reservation from Portal

• fix the membership of the slice• Use the add resource button in the portal

Option 2: Ensure common public key is loaded • distribute common public key to students• ask students to upload it in their profile• use corresponding private key to login

Ability to login can help in debugging!

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Common Problems

Problem: Can’t login to a node

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Can’t login to nodes: SSH

Login to all GENI compute resources using

ssh keys – no password

If you are ever prompted for a password during login to GENI nodes something is wrong

Using key-pair to SSH:– Public key: is public to everyone, loaded to

nodes

Private key: kept private in your computer, provided to SSH to verify it matches the loaded public key

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SSH Challenges

• Students might not be familiar with CLI

• Students might not be familiar with public key cryptography– Hard to distinguish between private and public– Hard to distinguish between password and

passphrase

http://groups.geni.net/geni/wiki/HowTo/LoginToNodes

Consider a brief SSH tutorial/intro

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SSH from Windows

SSH with keys from Windows is non-trivial– No standard ssh client that support keys (like openSSH)

Possible Solutions

http://groups.geni.net/geni/wiki/HowTo/LoginToNodes

Need to address this early!

– Pay software – eg SecureCRT– Linux VM – make use of a slim OS– Lab machine/campus resources– cygwin– FireSSH – javascript plugin for Firefox– PuTTy (private key format different)

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Common Problems

Problem: Can’t login to a node

Possible causes: – Wrong username– Public key isn’t loaded, Private key is wrong or non-existing– Private key has wrong permissions (it should have 0600)– Slice/sliver expired– Technical issue with node

Debug strategy:– Try logging in to the node yourself

• If successful look for the student account – cd ..; ls

• Look for loaded keys – sudo cat <student_user_path>/.ssh/authorized_keys

– Ask them to use ‘-v’ option• ssh –v foo@bar.example.net

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Common Problems

Problem: Can’t access AMs

Possible causes: – Firewall issues– AM is down

Debug strategy:– Check the GMOC calendars for planned/unplanned outages

• http://globalnoc.iu.edu/gmoc/index/support/gmoc-operations-calendars.html

– Verify access from campus (check the wireless!)– Have the student try to telnet to the port:

• e.g. telnet www.emulab.net 12369• http://groups.geni.net/geni/wiki/KnownGENIPorts

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Common Problems

Problem: Slice did not come up

Possible causes: – Student did not wait long enough– Problem with rspec

Debug strategy:– Check slice/sliver status yourself– Ask students to tell you the exact steps and try to replicate it– Use rspeclint on your rspecs

• http://www.protogeni.net/wiki/RSpecDebugging

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Common Problems

Problem: Omni is not working

Possible causes: – Computer is not connected to the internet/behind firewall– PATH/PYTHONPATH is not correct

• Python error

– omni is not configured

Debug strategy:– Check their PATH and PYTHONPATH variables:

• echo $PATH• echo $PYTHONPATH

– Verify connectivity to:• The internet (ping www.google.com)• To the AMs (telnet ch.geni.net 8443, telnet

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General debug advice

• Ask students to be specific about what is not working– Step-by-step run through usually helps

• Ask for what they see:– screenshots– omni output errors

• Gather as much information as you can– get slice name– tool they used– rspec

• Remember you have access to their slices, check for yourself!

• Contact help@geni.net for help• Register for resource mailing lists

– Better that you contact resource owners and not the students